I was asked if the above trick was deprecated because DVMT pre-alloc can be bypassed with some Whatevergreen patches but sometimes it's still needed.
For example, you want support for 4k display, DVMT will need to be increased and the bypass won't work.
It's not recommended for everyone since it can brick your system if done incorrectly. But you can still reset it back to default by setting the BIOS to load the default or remove all the batteries for a period of time.